Drive for nutators



Nov. 7, 1950 c. T. s. LOONEY 2,528,963

DRIVE FOR NUTATORS Filed Jan. 5, 1946 3 Sheets-Sheet 1 INVENTOR CHARLES 71 6. LOONE Y JLQQBW'M v ATTORNEY C. T. G. LOONEY DRIVE FOR NUTATORS Nov. 7, 1950 3 Sheets-Sheet 3 Filed Jan. 5, 1946 INVENTOR CHA/KES T G. LOO/VEY BY Mama? ATTORNEY Patented Nov. 7, 1950 DRIVE FOR NUTATORS Charles T. G. Looney, Silver Spring, Md., assignor to the United States of America as represented by the Secretary of the Navy Application January 5, 1946, Serial No. 639,375

The present invention. relates to means for providing a nutating motion and, more particularly, to a novel mechanism for selectively producing circular or elliptic motion and which may be utilized to produce nutatory movements of either circular or elliptic type. 7 An object of the invention is to provide a mechanism for producing circular orelliptic nu: tating motion at will, which is characterized by its inclusion of a planetary type of gearing.

Another object is to provide a mechanism of the character described in which the change from one type of nutating motion to the other is eifeeted by either locking part of the planetary gearing to another part ofthe gearing or releasing the first part and locking it to a stationary part of the mechanism.

A further object, is to provide amechanism of the character described in which. the changes from one type of nutating motion to the other may be effected while themechanism is operatbe understood by reierence to the accompanying drawings, in which h Fig. 1 is a perspective view showing one form of the new mechanism;

Fig. 2 is a side view of the mechanism, showing it applied to a short wave antenna;

Fig. 3 is a fragmentary side view on an enlarged scale, partly in section, showing part of the means for shiftin from one type of nutating motion to the other;

' Fig. 4 is a similar view showing the shifting means in a different position;

7 Fig. 5 is a longitudinal section of the mechanism, partly in elevation;

Fig. 6 is a sectional view on the plane indicated byline 6-6 in Fig.5, and

Fig. 7 is an end view of the mechanism, showjirig part of the planetary gearing.

Referring to the drawings, the mechanism is shown as comprising a motor I having a shaft 2 journalled on a bracket 2a and carrying a disk 3 rigidly secured thereon so as to turn at the full speed of the shaft at all times. A second disc 4 has a hub either integral therewith or suitably secured thereto, the hub having a bore 6 (Fig, 5) large enough to fit slidably and rotatably on the shaft 2. The axial motion of the disc 4 need be 6 Claims. (CI. 74-86) only relatively small, so that at one extremity thereof the disc 4 will bear against lugs 1 on the disc 3, while at its other extremity the disc 4 will bear against stationary brake element 8 mounted on brackets 8a.

Alined holes 9, l0 and H are provided in the disc 3 and its lugs I, the disc 4, and the brake element 8, so that a pin may be inserted through any adjacent pair of such holes to lock the disc 4 either to the rotatable disc 3 or the stationary brake element 8, when desired.

As will be described in detail presently, when disc 4 is thus locked to the rotating disc 3, a nutatory motion of circular type is provided, and when disc 4 is locked to the stationary brake element 8, an elliptic nutatory motion is provided. The insertion of the pin in either pair of adjacent holes 9, Ill and H, to provide this selective locking, may .be performed manually while the mechanism is stationary. Preferably, however, the mechanism includes means operable to change from circular to elliptic nutation and back again at will, without stopping the device completely to insert the pins manually in the holes 9-40 or l0-l l. The change means comprises a suitable mechanical device to shift the disc 4 axially in one direction or the other, while in rotation such as customary in belt shifting devices or clutches, or an electrical device such as shown. a

The electrical device here shown for shifting the disc 4 comprises an iron or steel disc l2 secured to the hub 5 to turn therewith, and two electromagnets i3 and [3a mounted on a stationary bracket [4 with the poles near and on opposite sidesof the disc I2, so as to pull it in either direction, depending on which magnet is energized. The magnets l3 and l3a may be energized selectively from a battery |3c through a selector switch I3d.

The latch pins I5 and I6 used with this form of device are preferably of lengths slightly exceeding the lengths of the respective bores 9 and H, in which they slide freely. These pins are located properly to enter the bore [0 of disc 4,

the ends of the pins adjacent disc 4 being rounded to facilitate their entry into bore [0. Pin I5 has an enlarged head l5a and similarly pin [6 has an enlarged head l6a, said heads being normally seated in enlarged outer ends of the respective bores, as shown. The heads 15a, 16a, serve to prevent the pins from passing toofar inward, and also receive the pressure from fiat springs [51) and 16b, held by screws I50 and l6c to the disc 3 and the stationary member 8, respectively. 4

later, by looking it .t -the brake The spring lfib permits the pin to yieldcutwardly during the preliminary slowing down period, and ultimately snaps the pin into bore l (Fig. 3).

When it is desired to cause disc 4 to rorapid rotation. For the same reason, a counterweight 26 may be provided on the other disc 2!, to balance the stud 2 la and the nutating mechanism 25 actuated thereby.

When the disc 4 is disconnected from the disc 3 and is held stationary by the pin [6 through holes H and I0, the gear 4a will remain at rest. However, as the. disc 3 ..is rotated by the shaft 2, the shafts 11 a will be c'arried around by disc 3 and cause the gears I! to turn shafts [1a in tate, the magnet !3a is energized instead, and

this will cause disc 4 to shift to. the right, thus V 15 l ld'willtu'rn the gears I8 and thus the gears 20, while at the-same time the disc 3 is turning about disengaging the pin l6 from {thebqre 'lli and, on the other hand; causing the right side of disc 4 (Fig. l) to bear against the lugs 'l of disc 3 pushing pin l5 to the right againstspringlfih'.

21 and the counterweight 26 will now move in The frictional engagement will cause d130,.4jtg

pick up speed, the bore l0 meanwhile riding over pin Ii which will snap into said bore Whenthe speedfof cisc 4 is high enough. The. disc 4 will thus be locked to disc 3, in the proper way to provide circular nutation, as will .be described later. I v A sun gear 4a is secured to the disc 4 to rotate therewith. Gears ll mesh with the sun gearAa and are carri d by shafts Ila journaled in the disc 3, but not connected in any Way. With the di c 4. so that rotation of thedisc 3,.mav take place even when disc 4 is locked in a'stationary position. In the lattercondition, of course, the gears l1 will rotate their shafts l'l'a, as the teeth of gears I1 rresh with those of sun gear. 4a, an example of the well known planetary type of gearing. i Each shaft lla'carries a gear I3 at its outer end. That is, the gears l! and lgwill ordinarily belocated on o posite side'sfof the disc 3, ,for convenience. although this isnot an e ential feature of the invention but merely simplifies the illustration (thereof. Shafts"!!! are jou'rnaled in the di c 3 for rotation. with respect theretoand each shaft 19 carries afgear 2!! rigid ther with, the gears 2n being in me h with the re pect v g ars J8 sojthat, when the disc 3 rotate indenendentlv offdisc 4, the gears 12!) will rotate and ,w ll was their shajitgl to turn corre pondingly. Each shaft lsj'carries alj disc 2| at it outer end. and rigid th rewith; sothat the e discs 2| will turn at thesamejspeed as the gears 2fi. One of the d c 21 carrie an eccentrically disposed stud 2la for a purpose to be de ed nr sentlvQ v The motor I and brackets 211,811 and H!v may be mount d on a base b ate'22. .The operation of this device is as'ffollo s:

, When the two discs 3 and 4 are locked together by the insertion of pin l5, through .holes'9 and It], obv ou lv the gears 4a and Il will move as a unit: that is.- no relative motion of. said -gears is pos ible. Con quently the shafts Ha -will merelv act a though they were rigid with the disc 3 and will hold the gears 2!} locked to disc 3. Thus, the discs 2| will merelv turnas though will move in a circular path around the axis of the shaft z. f 1

The stud 21a may be used to drive the nu tating device, and it may be remarked here that while two gear trains are shown, eachcomprising a set of gears ll, I8 and 20 and their connected shafts etc., only one such train is needed, the other bein pro ided only to secure dynamic balance ofv the entire assemblage, which normally is in hypocycloids.

their journals, since the gears H are meshed with gear 4a and must therefore rotate about their own axes as the disc 3 turns.

,This rotation of the gears I1 and their shafts its own axis. The result is that both the stud non-circular paths, which in general will be However, by selecting the number of teethof thevari'ous gears in the train in such awaythat the ang'ular velocity of each disc 2|, about its'jown axisgis twice that of the disc 3, the' stud 21a and counterweight 26 will. de-

scribe elliptic pathsthe min'or axis of said ellipse being equal'to the minimum distance from center to center Ofstud 2m. and 'c'ounterw'eight26 duringjr'otation, while themajor axis is'the correspending maximum distance. y In the specific device illustrated; this wouldgive a ratio of about 1 to 8 between the principal axesof the ellipse.

The,'positionsoffthese axes may be varied by proper'choice of the anfgiular'position of the stationary element 8 that is, the major axis may be. kept vertical; horizontaL; or in any desired intermediate direction, by moving the element 8 about the axis of shaft Z toa corresponding po- T I h :7 7 ,7; g.) .Oneuse to which,

invention may befapplied is shownin. Fig. 2 where a reflector 21, such as 'isuSed' in radarapparatus, is illustrated. An antenna suppor't 2721' for the dipole antenna 216 is located in fro nt ofthereflectornear or in the focal plane .ther eof and isfmounted at one end of a loar'28. Thisbar pass'esthroughthe middle of the .refiectio'nfwhere'fit lis mounted for pivotal motion in any di'rection, as 'by. means ,of a sphericaljoint 29. Atitsrear. end, the bar 28 has a sliding connectiom with a .rod 280., the rear end of which is bored to fit Iover the stud 2m withv sufficient; lqoseness to permit the disc 2| to rotate freely, so that the stud ZIa may carry said end of the 'rod 28a along in its motion. It will be evident that a nutating motion of the lever 28 and antenna fla will result.

The operation of the apparatus will be understoodfrom the above description of its structural embodiment. Assuming that it is desired to cause. the free end;of antenna support 2112 to travel in a circle, that, is -to cause the antenna support todescr-ibe; a-cone,'th eg discs 3 and 4. will be locked together, as byfinserting pin !5 into hole Iii, so that: they-,must turn as a unit with the motor shaft 2. All of thegears are thus 7 F locked, as;previously explained. andas a result rigidly secured to the disc 4, and the stud 2m 79 will describe a circleonce for every revolution of the motor shaft. 2.

.Assume now that the discs 3 and 4 are freed from one another by removalof the pin I5, and the pin I6 is inserted instead into holelll so as 5 to hold the disc 4. stationary While allowing disc 3 .to continue to rotate at motor speed. The gears IE will now travel around the stationary gear 4a, thus turning gears l1, shafts i'la, gears :I8'and 29, shafts I9 and discs 21. As stated, the

numbers of teeth on the various gears are such that the rotational speed .of each shaft I9 is twice that of the motor.

Starting from the position of stud 2Ia shown .in;Fi g.-1, when the disc 3 has made a quarter- The next quarter-turn of the disc 3 will, bring the stud 2 la to its lowermost position; that is, it y will be where counterweight 26 is'shownin Fig. 1. The next half-turn of disc 3 will, in a similar manner, return the stud 2 la to its initial position by way of the opposite side of the axis of shaft 2.

These positions will be repeated periodically together with all intermediate positions, the resulting path of stud 2 la in this case being an ellipse with its maior axis vertical. Of course, a similar motion will be produced in the antenna support 21a, the free end of which will thus travel in a similar ellipse with its major axis vertical, though not necessarily of the same length as that of the ellipse traveled by the stud 2 la.

As previously mentioned, the described ellipse is about eight times as long as it is wide with the specific proportions disclosed, but other ratios may be obtained by varying the distance from center to center of the shafts l9 and/or the distance of the stud 2 la from the axis of its shaft I9.

V fhile in some cases it may be preferable to have the major axis of the ellipse, described by the antenna, in a vertical direction, attention is called to the fact that the direction of this axis may be shifted at will by changing the location of the stationary element 8 circumferentially of the disc A. This member could also be replaced by a disc with a circularly arranged series of holes, any of which could be provided with a pin l6 for entering the hole If! in disc 4, whereby the maior axis of the described ellipse may be adjusted to differ nt an les of inclination.

What is claimed is:

l. A mechanism of the character described, com rising a rotatable drive shaft, an element on the shaft rotatable therewith, a second element loosely mounted on the shaft adjacent said first element and having a sun gear, planetary gearing on said first element meshing with the sun gear and including a driven shaft off et from the axis of said drive shaft, a stud eccentrically mounted on said driven shaft, a stationary member adiacent said second element, latch pins carried respectively by the stationary member and by the first element. for selectively connecting the second element to the stationary member or to said first element whereby the stud will describe an elliptical ath or a circular path, respectively, during rotation of the drive shaft, and means for shifting said second element to select the connection desired.

2. A mechanism of the character described, comprising a rotatable drive shaft, an element on the shaft rotatable therewith, a second element loosely mounted on the shaft adjacent said first element and having a sun gear, a driven shaft on the first element and oifset'from the axis of said drive shaft, a stud eccentrically will, either to the stationary member or to said first element, means for shifting said second element selectively into engagement with the desired one of said latching means, and planetary gearing on said first element meshing with said sun gear and having a driving connection to said driven shaft for rotating the driven shaft twice for each revolution of the drive shaft when said second element is connected to the stationary member, whereby the stud describes a circular path when the second element is connected to ,the first element and an elliptical path when the second element is connected to the stationary member.

3. A mechanism of the character described comprising a rotatable drive shaft, an element on "the shaft rotatable therewith, a stationary member adjacent the shaft, a second element loosely mounted on the shaft between said first element and the stationary member and having a sun-gean'a device for coupling said second element to the first e ement, a device for coupling the second element to the stationary member, means for sliding the second member longitudinally on the drive shaft to operate said coupling devices alternately, planetary gearing on said first element meshing with the sun gear and including a driven shaft offset from the axis of the drive shaft, and a stud mounted eccentrically on said driven shaft, whereby the stud describes an elliptical path when said second element is coupled to the stationary member and a circular path when the second element is coupled to said first element, during rotation of the drive shaft.

4. A mechanism of the character described comprising a rotatable drive shaft, an element on the shaft rotatable therewith, a stationary member adjacent the shaft, a second e ement loosely mounted on th shaft between said first element and the stationary member and having a sun gear, a device for coupling said second element to the first element, a device for coupling the second element to'the stat onary member, electromagnetic means for sliding the second member longitudinally on the drive shaft to operate said cou ling devices alternate y, planetary gearing on said first element meshing with the sun gear and including a driven shaft offset from the axis of the drive shaft, and a stud mounted eccentrically on said driven shaft, whereby the stud describes an elliptical path when said second element is coupled to the stationary member and a circular path when the second element is coup ed to sa d first element, during rotation of the drive shaft.

5. A mechanism of the character described comprising a rotatable drive shaft, an element on the shaft rotatable therewith, a stationary member ad acent the shaft, a second element loosely mounted on the shaft between said first element and the stationary member and having a sun gear, a device for coupling said second element to the stationary member in a predetermined position, a device for coupling the second element to said first element in a predetermined position relative thereto, means for sliding the second member longitudinally on the drive shaft to operate said coupling devices alternately, planetary gearing on said first element meshing with the sun gear and including a driven shaft offset from the axis of the drive shaft, and a stud mounted eccentrically on said driven shaft, whereby the stud describes an elliptical path when said second element is coupled to the stationary member and a circular path when the second element is coupled to said firstz'element, during rotation of the drive shaft;

' 6; A mechanism of the character described comprising a rotatable drive shaft, an element on the shaft rotatable therewith, a second element loosely mounted on the shaft adjacent said first element and having a sun gear, a driven shaft on thefirst element and offset from the axis of said drive shaft, a stud eccentrically mounted on said. driven shaft, a stationary member adjacent said second element, individual latching means for connecting the second element as desired, either to the stationary member or to said first element, during rotation of said drive shaft, means for moving said second element at will into engagement with the desired. one of said latching means, and planetary gearing on said first element meshing with said sun gear and having a driving connection to said driven shaft for rotating the driven shaft twice for each revolution of the drive shaft when said'second element is connected to the stationary member,

whereby the stud describes a circular path when REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS,

Number: Name Date 361,222 Jones et a1 Apr. 12, 1887 750,370 Kammerer Jan. 26, 1904 2,415,103 Langstrath Feb. 4-, 1947 FOREIGN PATENTS Number Country Date 129,805 Austria Oct. 10, 1932 322,659" France June 30,1902 

